Photographic test strip



0a. 29, 1940. c SPENCER 2,219,703

PHOTOGRAPHIC TEST STRIP Filed Dec. 4; 1939 7 45 4 4 fizz/9222 62" XL fizzyfao wbfig exm /v K 41% flaw 15 16 1.3 2 1 J11 .2 i

Patented Oct. 29, 1940 PATENT OFFICE PHOTOGBAPHIC TEST STRIP HarryChadwick Spencer, New York, N. Y.

Application December 4, 1939, Serial No. 307,387

2 Claims.

My invention relates to a device for making experimental tests todetermine the proper length of time for making photographic prints orenlargements.

Among the objects of my invention are to provide a device for makingsuch tests which can use the same section of the film at all times sothat the density of the tests on the test strip will not vary with thedensity of the film but. only with-the length of printing time; toprovide a device capable of making a series of identical picturesvarying only in density on a single test strip of photographic paper; toprovide-a device which will be economical and simple to use and whichwill insure more accurate determination of the proper length ofexposure; and such other objects, advantages and capabilities as willlater more fully appear and which are inherently possessed by myinvention. j

While I have shown in the accompanying drawing a preferred form of myinvention, yet I desire it understood that the same is susceptible ofmodification and change without departing from the spirit of myinvention.

Referring to the drawing, Fig. 1 is a perspective view showing the useof my strip tester with a conventional photo enlargement device; Fig. 2is a top plan view of my device; Fig. 3 is a longitudinal section of mydevice on line 33 of Fig. 2; Fig. 4 is a bottom plan view of my device;Fig. 5 is a detail sectional view on line 55 of Fig. 3; Fig. 6 is adetail sectional view on line I 66 of Fig. 3; Fig. '7 is a detailed viewof an assembled tape and test strip.

One embodiment selected to illustrate my invention comprises a bodymember III, which may be constructed of wood, metal or any desirablematerial. Adjacentpne end ofthe body member I is an aperture II which isnormally covered by a shutter l2. The shutter l2 may be temporarilymoved so as-to leave the aperture ll exposed.

Extending the full length beneath the body member II) are grooves l3adapted to hold an elongated tape 14 and a metal strip IS. The tape I4is attached to the metal strip l5, which strip l has an opening oropenings. l6 adapted to hold the sensitive photographic paper. Extendingfrom the end nearest which the aperture II is located is an extension 11comprised of a piece of leather or othersuitable material which isadapted to shield a portion of the sensitive paper with the body memberl0 or may be made in .insertion into the openings IE or by other suit- 5able means. The metal strip I5 is at this time adjacent the same end ofthe body member ID as the aperture H. The tape l4 may then be pulledfrom the other end until a portion of the photographic strip I8 is belowthe aperture ll. 10 By displacing the shutter I! a portion of the stripmay be exposed to the light from the enlarger which passes through thenegative which is to be printed or enlarged. The tape i4 may then bepulled further so as to expose the next section of the photographicstrip I! in the same manner as before. The portions of the photographicstrip i8 which have not been exposed are shielded by the extension I!which extends from the body member Hi. The tape l4 may be marked in anyappropriate manner to indicate the correct distance it should be pulledto expose the next section of photographic paper.

It will be noted that the use of my test device results in a series ofexposures of varying lengths of time, all made from the same section offilm. There is no danger of variance in the density of the prints due tovariance in the density of different portions of the film. There sodesires.

Instead of providing the extension I! to shield the unexposed portion ofthe photographic strip, or the exposed portion if the direction ofmovement is the opposite of that described above, the body member Hi maybe so constructed that the strip will pass or remain in or beneath thebody member 10 and thus eliminate the extension ll. 40

My device is simple in construction and use so that photographers willhave no difllculty in determining the proper time of'exposure to usewhen making photographic enlargements.

Having thus described my invention, I claim:

1. A device for determining the proper time of exposure for photographicprints or enlargements comprising a body member having an openingadjacent one end, a shutter normally covering said opening, said shuttermounted on the upper portion of said body member adjacent the openingand slidable along the length of said body member to uncover saidopening, a tape slidably mounted within the bottom of said body member,holding means attached to said tape to photographic paper, said tape,holding means and photographic paper being slidable along the length ofsaid body member so as to expose successive portions or saidphotographic paper beneath said opening and shutter for vvarious lengthsor exposure, and means for shielding the remainder of said photographicpaper from exposure;

2. A device for determining the proper time of exposure for photographicprints or enlargements comprising a body memberhaving an openingadjacent one end, a shutter normally covering said opening, said shuttermounted on the upper portion or said body member adjacent the openingand slidable along the length or said body member to uncover saidopening,

a tape slidably mounted withimthe bottom of said body member, holdingmeans attached to said tape to receive and hold the end oi a strip orsensitive photographic paper, said tape, holding means and photographicpaper being slidabie along the length or said body member so as toexpose successive portions oi said photographic paper beneath saidopening and shutter for various lengths of exposure, said tape havingmarkings corresponding in size to said opening so as to indicate thecorrect distance or movement for exposing said portions, and means forshielding the remainder of said photographic paper from exposure.

HARRY cmnwrcx SPENCER.

